//实现一个函数ex2，能够使用fp.first获取列表的第一个元素
const fp = require('lodash/fp')
const {Maybe,Container} = require('./03-code')
let xs = Container.of(['do','ray','me','fa','so','la','ti','do'])
let ex2 = () => { 
  //需要实现的函数
  let r = xs
        .map(x => fp.first(x))
  console.log(r,xs)
}
ex2()